Gene therapy has been proposed as an approach to the treatment of ocular diseases by a number of investigators. Hermens et al. (J. Neurosci. Methods 71:85-98 (1997)) disclosed the injection of an adenoviral vector containing a lacZ gene as a reporter gene into the central and peripheral nervous system of the rat. In that system areas with a laminar structure such as the eye demonstrated more widespread transgene expression. Ali et al. (Hum. Mol. Genet. 5:591-5949 (1996)) disclosed the use of an adeno-associated virus (AAV) as a vector carrying lacZ to transduce all layers of the neuroretina as well as the retinal epithelium following subretinal injection. Mashhour (Gene Ther. 1:122-126 (1994)) disclosed that injection of an adenovirus vector carrying lacZ into the vitreous body, the anterior chamber, or the peribulbar body of mice did not result in any detectable cytopathic effect and was associated with endocytosis of viral particles in corneal, photoreceptor, bipolar, ganglionic, and oculomotor muscle cells, depending on the administration route.
The use of gene therapy to treat heritable diseases of the eye in particular has been proposed by several researchers. For example, Li et al. (Proc. Natl. Acad. Sci. U.S.A. 92:7700-7704 (1995)) disclosed the use of adenovirus-mediated transfer of human beta-glucuronidase cDNA expressed under the control of a non-tissue specific promoter injected intravitreally or subretinally to reverse the pathological changes of lysosomal storage disease in the eyes of mice with mucopolysaccharidosis VII.
Rescue of photoreceptors by gene therapy has been demonstrated in several experimental systems. Cayouette and Gravel (Hum. Gene Ther. 8:423-430 (1997)) disclosed adenovirus-mediated gene transfer of ciliary neurotropic factor prevented photoreceptor degeneration in the retinal degeneration (rd) mouse, an animal model of retinitis. pigmentosa Bennett et al. (Hum. Gene Ther. 7:1763-1769 (1996)) disclosed the rescue of photoreceptor cells in rd mice using a recombinant replication defective adenovirus containing murine cDNA for beta phosphodiesterase. Dunaeif et al. (Hum. Gene Ther. 6:1225-1229 (1995)) disclosed retroviral gene transfer into retinal pigment epithelial cells followed by transplantation into rat retina in an experimental rat model to preserve photoreceptors.
The use of suicide genes delivered by recombinant viral vectors to kill ocular cells has focused mainly on the use of the herpes thymidine kinase gene. For example, Sakamoto, et al. (Ophthalmology 102:1417-1424 (1995) described the inhibition of experimental proliferative vitreoretinopathy by retroviral vector-mediated transfer of the herpes simplex thymidine kinase gene. Murata et al. (Ophthalmic Res. 29:242-251 (1997) described the use of retroviral vectors to transfer the herpes simplex virus thymidine kinase gene in a rabbit model of proliferative vitreoretinopathy.
The role of tumor suppressor genes such as p16, p21, p53, or RB in hyperproliferative diseases of the eye has been challenging to elucidate. Studies of cell cycle regulation in the ocular lens using transgenic mice have shown that inactivation of RB can cause postmitotic lens fiber cells to enter the cell cycle. However, when p53 is present, inactivation of RB in this cell type results in cell death rather than continued proliferation. Although p53 is known to upregulate expression of the cyclin-dependent kinase inhibitor p21, overexpression of p21 in transgenic lens is not sufficient to cause apoptosis in transgenic mouse lens (Fromm et al. Dev. Genet. 20:276-287 (1997)). In vascular tissue, Chang et al. (J. Clin. Invest. 96:2260-2268 (1995)) discloses that adenovirus mediated overexpression of p21 inhibits vascular smooth muscle cell (VSMC) proliferation in vitro by arresting VSMCs in the G1 phase of the cell cycle. In addition, Chang, et al. demonstrated that localized adenoviral delivery of p21 in conjunction with balloon angioplasty significantly reduced neointima hyperplasia in the rat carotid artery model of restenosis.
The present invention discloses methods and compositions for the treatment of ocular diseases. In particular, the present invention provides a method for the treatment of ocular hyperproliferative diseases by the administration of cyclin dependent kinase inhibitors. The present invention further provides pharmaceutical formulations for the intracellular delivery of cyclin dependent kinase inhibitors.